Effect of platelet-rich plasma on the acceleration of graft bone catabolism in lateral lumbar interbody fusion in a short-term assessment

This study aimed to demonstrate whether impregnating the graft bone with platelet-rich plasma (PRP) accelerates graft bone catabolism in lateral lumbar interbody fusion (LLIF). Consecutive patients who underwent LLIF were assessed. Of the two spaces for bone grafts in the intervertebral cage, one space was filled with graft bone impregnated with PRP, and the other was filled with graft bone without PRP, which divided the graft bones into PRP and non-PRP groups. The mean Hounsfield units (HU) of the graft bone at the center of the cage space in the coronal and axial slices were measured using computed tomography (CT) images 1 week and 6 months after surgery. The delta value of HU from 1 week to 6 months after surgery was calculated for the PRP and non-PRP groups. We compared the delta values of the HU between the two groups. The PRP and non-PRP groups comprised 16 bone grafts. In the coronal slices, the HU value in the PRP group (delta value: 526.1 ± 352.2) tended to have a greater decrease at 6 months after surgery compared with that in the non-PRP group (delta value: 217.6 ± 240.4) (p = 0.065). In the axial slices, the HU value in the PRP group (delta value: 501.3 ± 319.6) was significantly decreased at 6 months after surgery compared with that in the non-PRP group (delta value: 159.2 ± 215.3) (p = 0.028). Impregnating the graft-bone with PRP accelerated graft bone catabolism in LLIF within 6 months after surgery.

The Effectiveness of Leukocyte-Poor Platelet-Rich Plasma Injections for Symptomatic Mild to Moderate Osteoarthritis of the Knee With Joint Effusion or Bone Marrow Lesions in a Japanese Population: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

BACKGROUND

Intra-articular platelet-rich plasma (PRP) injections have been proposed for the treatment of knee osteoarthritis (OA); however, their effectiveness in Japanese patients remains unclear.

PURPOSE

To investigate whether 3 intra-articular injections of leukocyte-poor PRP (LP-PRP) improve symptoms and joint function in symptomatic Japanese patients with mild to moderate knee OA.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

Of 72 patients screened, 30 were included and randomized to receive LP-PRP (n = 15) or saline (placebo; n = 15) injections between March 2019 and February 2023. Patients attended a screening visit and 3 treatment visits at 1 week apart, followed by 3 follow-up visits (at 4, 12, and 24 weeks) after the initial treatment visit. The primary efficacy outcome measure was the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, whereas the secondary efficacy outcome measures were the proportion of patients showing a visual analog scale (VAS) improvement of ≥50%. Magnetic resonance imaging was performed to evaluate joint effusion and bone marrow lesions using the Whole-Organ Magnetic Resonance Imaging Score. Patients were followed for 24 weeks.

RESULTS

Patients in the PRP group (mean age, 65.9 years) had a mean hip-knee-ankle angle of 5.1°, with 7 and 8 patients demonstrating Kellgren-Lawrence grade 2 and 3 knee OA, respectively. Patients in the placebo group (mean age, 67.9 years) had a mean hip-knee-ankle angle of 3.8°, with 6 and 9 patients showing Kellgren-Lawrence grade 2 and 3 knee OA, respectively. No significant differences were identified in any baseline factors. The percentage change in Western Ontario and McMaster Universities Osteoarthritis Index scores from baseline to 24 weeks was significantly different (P= .032) between the PRP (median, 75.9%; quantile 1 [Q1], 49.6; quantile 3 [Q3], 94.1]) and placebo (median, 27.7%; Q1, -9.4; Q3, 80.9]) groups. Overall, 73.3% and 28.6% of the PRP group and placebo group, respectively, exhibited an improvement in visual analog scale scores of ≥50%, with a significant improvement observed in the PRP group (P = .027). Changes in bone marrow lesions from baseline to 24 weeks, as assessed on magnetic resonance imaging, significantly differed between groups (P = .017), with no significant differences in other secondary endpoints.

CONCLUSION

In Japanese patients with knee OA, 3 intra-articular LP-PRP injections led to clinical improvements at 24-week follow-up and significant functional improvements and pain relief after 24 weeks.

Effects of bone marrow-derived mesenchymal stem cell transplantation in piglet Legg-Calve-Perthes disease models: a pilot study

This preliminary study investigated the efficacy and safety of bone marrow-derived mesenchymal stem cell transplantation in a piglet Legg-Calve-Perthes disease (LCPD) model. The LCPD model was induced in two Landrace piglets (6- and 7-week-old, weighing 12 and 17 kg, respectively) by ligaturing the femoral neck. In the first piglet, the natural LCPD course was observed. In the second piglet, 4 weeks after ligaturing the femoral neck, simple medium and medium containing 2.44 × 10 7 bone marrow-derived mesenchymal stem cells were transplanted into the right and left femoral heads after core decompression, respectively. Plain radiographs were obtained every 4 weeks, and the epiphyseal quotient was calculated by dividing the maximum epiphysis height by the maximum epiphysis diameter. The piglets were sacrificed at 14 weeks postoperatively. The femoral heads were extracted and evaluated grossly, pathologically, and by using computed tomography. The transplanted cell characteristics were evaluated using flow cytometry. Flattening of the epiphysis was observed in both femoral heads of the first piglet and only in the right hip of the second piglet. The epiphyseal quotients immediately and at 14 weeks postoperatively in the right femoral head of the second piglet were 0.40 and 0.14, respectively, while those of the left femoral head were 0.30 and 0.42, respectively. Hematoxylin and eosin staining did not reveal physeal bar or tumor cell formation. The transplanted cells were 99.2%, 65.9%, 18.2%, and 0.16% positive for CD44, CD105, CD29, and CD31, respectively. Core decompression combined with bone marrow-derived mesenchymal stem cell transplantation prevented epiphyseal collapse.

Association of non-steroidal anti-inflammatory drug use with encephalopathy development: An analysis using the United States Food and Drug Administration Adverse Event Reporting System (FAERS) and Japanese Adverse Drug Event Report (JADER) databases

Encephalopathy is the most severe complication of various common infections, including influenza and herpes, and it often results in death or severe neurological disability. The risk factors for viral encephalopathy include non-steroidal anti-inflammatory drug (NSAID) use; however, studies on NSAID-related encephalopathy are limited. In this study, we aimed to investigate the characteristics of NSAID-related encephalopathy. We investigated the incidence of NSAID-related encephalopathy using data from the United States Food and Drug Administration Adverse Event Reporting System (FAERS) and Japanese Adverse Drug Event Report (JADER) databases containing reports on spontaneous adverse effects (AEs) published by the Pharmaceuticals and Medical Devices Agency. We used these databases to detect AEs based on reported odds ratios. By separating suspicious drugs, concomitant drugs, and drug interactions involving NSAIDs, we investigated the relationship between encephalopathy pathology and AEs of NSAIDs. Significant encephalopathy signals were detected for loxoprofen and etodolac in the FAERS database and loxoprofen in the JADER database. In the JADER database, significant encephalopathy signals in loxoprofen-treated patients were detected in 70-79-year-old, ≥80-year-old, influenza viral infection, and herpes virus infection groups. Significant encephalopathy signals in patients with herpes virus infection were detected in the ≥80-year-old and loxoprofen-treated groups. Regarding the involvement of loxoprofen in the development of encephalopathy, the JADER database listed loxoprofen as a suspect drug, without indicating any concomitant drug interactions. In conclusion, our findings suggest that loxoprofen and etodolac may be associated with viral encephalopathy. Accordingly, prudence is recommended when using loxoprofen in older individuals with viral infections.

Safety and feasibility of in-hospital autonomous transportation using a driverless mobility for patients with musculoskeletal disorders: preliminary clinical study to achieve mobility as a service in medical care

BACKGROUND

Recent advancements in and the proliferation of autonomous mobility technology, such as intelligent wheelchairs, have made it possible to provide mobility services for patients with reduced mobility due to musculoskeletal disorders. In the present study, we conducted a preliminary clinical study to assess the safety and feasibility of in-hospital autonomous transportation using a driverless mobility (wheelchair) for patients with musculoskeletal disorders.

METHODS

From January to February 2022, 51 patients with musculoskeletal disorders exhibiting gait disturbance who presented to our institution were included in the present study. Driverless mobility rides were conducted over a straight-line distance of 100 m from the orthopaedic outpatient reception to the payment counter after the outpatient consultation. We assessed the quality of life using an EQ-5D-5 L index and pain using a VAS score before riding the mobility to investigate the patient's condition. After the ride, a questionnaire survey was conducted to assess patient satisfaction on a 5-point scale. In addition, adverse events during the mobility ride were investigated.

RESULTS

Overall satisfaction levels showed that 44 out of 51 (86%) patients rated the level as 3 or higher. There were no significant differences in the level of satisfaction based on the cause of disorders or EQ-5D-5 L Index. Among 19 patients who rated the level of satisfaction as 2-3, the ratio of postoperative patients and those with pain tended to be higher (p < 0.05). While 26 of 51 (51%) patients reported moments of feeling unsafe during the mobility ride, no actual adverse events, such as collisions, were observed.

CONCLUSIONS

An in-hospital autonomous transportation service using a driverless mobility for patients with musculoskeletal disorders demonstrated high satisfaction levels and was safe with no severe adverse events observed. The expansion of autonomous mobility deployment is expected to achieve mobility as a service in medical care.

Single-Joint Type Hybrid Assistive Limb for Knee Training in the Acute Postoperative Phase After Opening Wedge High Tibial Osteotomy: A Feasibility and Safety Trial

BACKGROUND AND OBJECTIVE

Opening wedge high tibial osteotomy (OWHTO) influences the knee extensor mechanism, the range of passive motion of knee extension and persistent quadriceps, and anterior knee pain and weakness. Rehabilitation should focus on quadriceps strength and improving joint mobility. The single-joint hybrid assistive limb device (HAL-SJ) is a wearable exoskeleton cyborg. In this study, we investigated the feasibility and safety of HAL-SJ training after the early postoperative period following OWHTO and whether the use of this device can improve functional outcomes, including knee muscle extensor strength and knee extension range of motion without knee pain.

METHODS

Patients who had been diagnosed with knee osteoarthritis and had undergone OWHTO were assessed for eligibility in this prospective trial conducted at our institution between June 2015 and November 2020. The participants were split into two groups, i.e., 10 patients in the hybrid assistive limb (HAL) group and eight patients in the control group. We initiated HAL-SJ therapy on postoperative day 8 and continued it until the patient's discharge. During the hospitalization period, patients engaged in HAL-SJ-assisted knee extension exercises. This exercise routine encompassed five sets, each comprising 10 repetitions, and was conducted twice a week. We conducted assessments aimed at detecting any potential adverse events that could be linked to HAL training. Assessment of the knee extension angle via the visual analog scale (VAS) and strength assessments using a hand-held dynamometer (HHD) were conducted. To compare clinical outcomes before and after OWHTO, knee extension angle, the VAS, HHD, Japanese Orthopaedics Association (JOA) score, and the Japanese Knee Osteoarthritis Measure (JKOM) were assessed at four distinct time points.

RESULTS

No adverse events were observed during the study. The assessment of clinical outcomes before and after OWHTO demonstrated a gradual improvement in outcomes.

CONCLUSION

The single-joint hybrid assistive limb device in patients who underwent OWHTO appears to be potentially safe. It contributed to enhanced muscle activity efficiency by reducing knee pain and improving knee extension angles in the early postoperative phase.

Muscle Strength and Efficiency of Muscle Activities Recovery Using Single-Joint Type Hybrid Assistive Limb in Knee Rehabilitation after Anterior Cruciate Ligament Reconstruction

Decreased muscle strength often occurs after anterior cruciate ligament (ACL) reconstruction; this can include muscle atrophy, neuromuscular dysfunction, and reduced force generation efficiency. Hybrid assistive limb (HAL) technology, which integrates an interactive biofeedback system connecting the musculoskeletal system to the brain and spinal motor nerves, offers a potential intervention. Our study, conducted from March 2018 to August 2023 using knee HAL single-joint technology, was a prospective non-randomized controlled trial involving 27 patients who had undergone arthroscopic ACL reconstruction. They were split into two groups: HAL (18 patients) and control (nine patients). Beginning 18 weeks after their surgery, the HAL group participated in three weekly sessions of knee HAL-assisted exercises. Both the HAL and control groups underwent isokinetic muscle strength tests at postoperative weeks 17 and 21. Testing utilized an isokinetic dynamometer at 60°/s, 180°/s, and 300°/s. The Limb Symmetry Index (LSI) was employed to measure side-to-side differences. The HAL group showed significant LSI improvements in peak extension torque across all testing velocities and for peak flexion torque at 60°/s and 300°/s. The rate of change in LSI for peak flexion torque at 300°/s was significantly higher post-measurements (p = 0.036; effect size = 1.089). The change rate for LSI in peak extension torque at 300°/s and all peak flexion torques showed medium to large effect sizes in Cohen's d. In conclusion, knee HAL single-joint training positively influenced muscle strength recovery and efficiency. The HAL training group exhibited superior muscle strength at various isokinetic testing velocities compared to the control group.

Comparing Bone Fusion Rates Between Novel Unidirectional Porous Tricalcium Beta-Phosphate and Autologous Bone in Lumbar Lateral Interbody Fusion: A Two-Year Radiographic Outcome Study

This retrospective cohort study aims to examine the potential differences in bone fusion between autologous bone and artificial bone in the lumbar lateral interbody fusion at 2two years post-surgery. The bone fusions performed in 15 cases and at 34 intervertebral levels were compared to assess the differences between the artificial bone, Affinos® (Kuraray Co., Tokyo, Japan), and autogenous bone. Two years post-surgery, we evaluated computed tomography (CT) multi-planar reconstruction images in the coronal and sagittal planes. One year after surgery, out of the 24 windows, 17 (70.8%) windows transplanted with autologous bones showed bone fusion. Additionally, out of the 38 windows, 18 (47.4%) windows transplanted with Affinos® showed bone fusion. Two years post-surgery, out of the 24 windows, 19 (79.2%) windows transplanted with autologous bones showed bone fusion. Additionally, out of the 38 windows, 30 (79.0%) windows transplanted with Affinos® showed bone fusion, and no difference was observed in the fusion rate at two years post-surgery (P = 0.238). In cases using Affinos® for transplanted bone, the bone fusion rate increased between one and two years. The rate of bony fusion using Affinos® in lateral lumbar interbody fusion (LLIF) cages is at par with that of autologous bone grafts at two years post-surgery. Affinos® is a promising candidate for graft material in LLIF surgery.

Bilateral Knee Osteoarthritis Treated With Medial Open-Wedge High Tibial Osteotomy Using Two Types of β-Tricalcium Phosphate With Differing Placements in Each Knee: A Report of Two Cases

In medial open-wedge high tibial osteotomy (MOWHTO) for knee osteoarthritis, synthetic bone is commonly used as a replacement material for the opening gap. Unidirectional porous β-tricalcium phosphate (UDPTCP) and spherical porous β-tricalcium phosphate (SPTCP) have been widely used in this regard. In general, the two prostheses are placed parallel to the osteotomy opening gap. In this report, we discuss two cases involving a 63-year-old woman and a 51-year-old man who underwent MOWHTO for bilateral knee osteoarthritis. Both patients had experienced bilateral knee pain. In both patients, UDPTCP was placed anteriorly and SPTCP was placed posteriorly in one knee, with the placement reversed in the other knee. The remodeling of each type of β-TCP was evaluated using CT immediately after the surgery and one year postoperatively. The postoperative corrective loss and clinical outcomes were also evaluated. Remodeling with β-TCP was found to be faster with UDPTCP than with SPTCP, even though the anteroposterior placement differed laterally in each patient. Furthermore, there was no correction loss, and the clinical outcomes were comparable, regardless of the placement of β-TCP.

Efficacy of platelet-rich plasma impregnation for unidirectional porous β-tricalcium phosphate in lateral lumbar interbody fusion: study protocol for a prospective controlled trial

BACKGROUND

The use of platelet-rich plasma has been increasing in spinal fusion surgery. However, the efficacy of platelet-rich plasma in lateral lumbar interbody fusion is unclear. In Japan, Affinos,® (Kuraray Co., Tokyo, Japan), a β-tricalcium phosphate artificial bone, has been increasingly used for spinal fusion. The purpose of this trial is to demonstrate whether Affinos® impregnated with platelet-rich plasma can achieve a higher fusion rate and better clinical outcomes than Affinos® alone.

METHODS

The current study is a prospective randomized controlled trial. This trial will include consecutive patients scheduled for lateral lumbar interbody fusion. An intervertebral cage for lateral lumbar interbody fusion has two spaces for bone grafts. As a consequence, two bone grafts are inserted at each intervertebral level. In this study, an artificial bone with platelet-rich plasma will be inserted into one space, and an artificial bone without platelet-rich plasma will be inserted into the other space. We will compare the fusion rates between the bone grafts with and without platelet-rich plasma. Our primary endpoint will be the interbody fusion rate at 1 year after surgery.

DISCUSSION

This trial will verify the efficacy of platelet-rich plasma with Affinos® for bony fusion in lateral lumbar interbody fusion. It will also provide substantial evidence for the effectiveness and safety of platelet-rich plasma in spinal fusion surgery.

TRIAL REGISTRATION

Japan Registry of Clinical Trials (jRCT) jRCTb032200199 . First registered on 13 November 2020. jRCT is approved as a member of the Primary Registry Network of WHO ICTRP.

Joint effusion at 3 months after anterior cruciate ligament reconstruction is associated with reinjury

PURPOSE

To evaluate whether joint effusion at 3 months after anterior cruciate ligament (ACL) reconstruction is associated with ACL reinjury.

METHODS

The medical records of 227 consecutive patients who underwent single-bundle ACL reconstruction between 2015 and 2018 were reviewed in this retrospective single-center study. Demographic data such as sex and age at surgery, as well as data on preinjury Tegner activity scale score, time from injury to surgery, presence of meniscus and cartilage injuries, and the occurrence of ACL reinjury within 2 years, were collected. Joint effusion was defined as grade 3 (range 0-3) according to the ACL Osteoarthritis Score by magnetic resonance imaging at 3 months postoperatively. Multivariate logistic regression analysis was performed to control for potential confounders.

RESULTS

A total of 176 patients (mean age 22.5 ± 9.9 years) were included. Among these patients, 18 (10.2%) had ACL reinjury. At the multivariate logistic regression analysis, higher Tegner activity scale (odds ratio [OR] 3.12; 95% confidence interval [CI] 1.61-6.04; p < 0.001) and presence of joint effusion (OR 34.5; 95% CI 6.63-179.7; p < 0.001) increased the odds of ACL reinjury, and older age (OR 0.68; 95% CI 0.51-0.92; p = 0.012) decreased the odds of ACL reinjury.

CONCLUSIONS

Joint effusion with a larger fluid volume at 3 months postoperatively was one of the risk factors for ACL reinjury independent of confounders, such as age and activity level. This result suggests the possibility of postoperative intervention for ACL reinjury.

LEVEL OF EVIDENCE

III.

Comparison Between Concentrated Autologous Bone Marrow Aspirate Transplantation as a Hip Preserving Surgery and Natural Course in Idiopathic Osteonecrosis of the Femoral Head

Purpose The purpose is to compare the therapeutic efficacy of concentrated autologous bone marrow aspirate transplantation (CABMAT) with that of observation alone for osteonecrosis of the femoral head (ONFH). Methods This single-center study included patients with idiopathic ONFH that were either treated with CABMAT (CABMAT group) or managed through observation alone (observation group) over a >2-year follow-up period. The Japanese Investigation Committee classification was used to diagnose and classify ONFH. The collapse rates for stages 1 and 2 ONFH (i.e., pre-collapse stages) and the THA conversion rates were compared between the CABMAT and observation groups. Results The CABMAT and observation groups comprised 232 (mean follow-up: 8.2 years) and 106 (mean follow-up: 6.0 years) patients, respectively. No significant intergroup differences were noted in the stages, types, and associated factors of ONFH. The collapse rates for pre-collapse stages in the CABMAT and observation groups were 67.1% and 65.3%, respectively. For stage 1, the collapse rates were significantly lower in the observation group than in the CABMAT group (p<0.05). The overall THA conversion rates in the CABMAT and observation groups were 24.3% and 41.5%, respectively (p<0.0001). For ONFH of stages 3A and 3B (collapse stages), the THA conversion rates were significantly lower in the CABMAT group (p<0.05). Conclusion Collapse rates were significantly higher for stage 1 ONFH; for collapse stages, the THA conversion rates were significantly lower in the CABMAT group than in the observation group. Therefore, observation and CABMAT are recommended for ONFH of stage 1 and for ONFH of higher stages, respectively.

Total Hip Arthroplasty After Failed Hip-Preserving Surgery with Concentrated Autologous Bone Marrow Aspirate Transplantation for Osteonecrosis of the Femoral Head: A Retrospective Study

PURPOSE

Since 2003, a hip-preserving technique-concentrated autologous bone marrow aspirate transplantation (CABMAT)-has been applied to treat osteonecrosis of the femoral head (ONFH). We investigated intraoperative and postoperative outcomes of total hip arthroplasty (THA) in patients who underwent CABMAT as hip-preserving surgery for ONFH but developed secondary hip osteoarthritis after progressive femoral head collapse.

METHODS

A total of 456 hips in 282 patients underwent CABMAT in our hospital between April 2003 and December 2018; 108 hips required THA (THA conversion rate, 23.7%). We enrolled 60 hips (26 hips in 20 men and 34 in 26 women) with a follow-up of over 2 years. We retrospectively analyzed patient background data, time to THA, surgical procedure, postoperative complications, and clinical outcomes from medical records.

RESULTS

The disease was steroid-related, alcohol-related, and idiopathic in 48, seven, and five hips, respectively. The mean age at THA was 45.7 years, and mean conversion time was 2.7 years. Cementless THA was performed in all cases; the mean operating time and blood loss were 82.7 min and 210 g, respectively. Postoperative complications were observed in four cases; intraoperative fracture, two cases; superficial infection, one case; and dislocation, one case. The mean follow-up period was 5.7 years; no loosening or deep infections occurred. No patients required revision arthroplasty.

CONCLUSION

We noted no complications related to CABMAT. After a minimum 2-year follow-up, the clinical outcomes were good. CABMAT was found to be an useful hip-preserving surgery, with little effect on conversion to THA, and THA outcomes were good.

Single-joint Hybrid Assistive Limb in Knee Rehabilitation after ACL Reconstruction: An Open-label Feasibility and Safety Trial

Objectives:

Methods:

Results:

Conclusions:

Novel susceptibility loci for steroid-associated osteonecrosis of the femoral head in systemic lupus erythematosus

INTRODUCTION

Osteonecrosis of the femoral head (ONFH) involves necrosis of bone and bone marrow of the femoral head caused by ischemia with unknown etiology. Previous genetic studies on ONFH failed to produce consistent results, presumably because ONFH has various causes with different genetic backgrounds and the underlying diseases confounded the associations. Steroid-associated ONFH (S-ONFH) accounts for one-half of all ONFH, and systemic lupus erythematosus (SLE) is a representative disease underlying S-ONFH. We performed a genome-wide association study (GWAS) to identify genetic risk factors for S-ONFH in patients with SLE.

METHODS

We conducted a two-staged GWAS on 636 SLE patients with S-ONFH and 95 588 non-SLE controls. Among the novel loci identified, we determined S-ONFH specific loci by comparing allele frequencies between SLE patients without S-ONFH and non-SLE controls. We also used Korean datasets comprising 148 S-ONFH cases and 37 015 controls to assess overall significance. We evaluated the functional annotations of significant variants by in-silico analyses.

RESULTS

The Japanese GWAS identified four significant loci together with 12 known SLE susceptibility loci. The four significant variants showed comparable effect sizes on S-ONFH compared with SLE controls and non-SLE controls. Three of the four loci, MIR4293/MIR1265 (OR = 1.99, P-value = 1.1 × 10-9), TRIM49/NAALAD2 (OR = 1.65, P-value = 4.8 × 10-8) and MYO16 (OR = 3.91, P-value = 4.9 × 10-10), showed significant associations in the meta-analysis with Korean datasets. Bioinformatics analyses identified MIR4293, NAALAD2 and MYO16 as candidate causal genes. MIR4293 regulates a PPARG-related adipogenesis pathway relevant to S-ONFH.

CONCLUSIONS

We identified three novel susceptibility loci for S-ONFH in SLE.

Characterization of bone remodeling of two different porous types of β-tricalcium phosphates: a quantitative site-by-site analysis using computed tomography

This study compared the process of bone remodeling using spherical porous β-tricalcium phosphate (SPTCP) and unidirectional porous β-tricalcium phosphate (UDPTCP) by quantitative computed tomography (CT) analysis. We retrospectively analyzed the data of 16 patients (4 men, 12 women; age, 43-78 years) who underwent medial opening wedge high tibial osteotomy (MOWHTO) and were followed up for 1 year postoperatively. Nine patients used SPTCP spacers and seven patients used UDPTCP spacers. CT was performed at 1 week, 6 months, and 1 year postoperatively. CT attenuation values were measured at three sites on the axial slice and sagittal slice, i.e., the superior, center, and inferior sites and the lateral, center, and medial sites for UDPTCP and SPTCP, respectively. CT attenuation values were lower for UDPTCP than for SPTCP in all sites at 6 months and 1 year postoperatively (p < 0.05). CT attenuation values decreased in the superior and inferior sites for UDPTCP (p < 0.05), and CT attenuation values decreased in the lateral site for both SPTCP and UDPTCP (p < 0.05). The process of bone remodeling differed between the two over a short-term follow-up of 1 year postoperatively.

A Retrospective Analysis of Clinical Outcome and Predictive Factors for Responders with Knee Osteoarthritis to a Single Injection of Leukocyte-Poor Platelet-Rich Plasma

Although various platelet-rich plasma (PRP) kits are commercially available, the efficacy of these kits for knee osteoarthritis (KOA) has not been fully investigated. This study aimed to investigate the short-term results of leukocyte-poor PRP (LP-PRP) and the factors that contribute to its efficacy. We retrospectively reviewed 124 patients with KOA who were treated with LP-PRP. White blood cell (WBC) and platelet counts in the whole blood and the LP-PRP were measured. KOA severity was assessed using radiography. Clinical evaluation was performed both prior to injection and after an average of 3.3 weeks after the injection using the Japanese Knee Osteoarthritis Measure (JKOM). Responders were defined based on the JKOM. The contributing factors for responders were examined using a multivariate logistic analysis. The responder rate was 58.1% and the contributing factors for responders were a higher visual analog scale score before injection, WBC count in whole blood, and platelet concentration ratio of LP-PRP. The LP-PRP improved the clinical scores in the short term. Certain patient characteristics before injection and the concentration ratio of LP-PRP may be predictors of its efficacy; these may provide clues for elucidating which components of LP-PRP act on KOA pathologies.

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

Use of unidirectional and spherical porous β-tricalcium phosphate in opening-wedge high tibial osteotomy: a case series

Introduction: Unidirectional porous β-tricalcium phosphate (UDPTCP) consists of a novel porous artificial bone that is structurally different from conventional artificial bone comprised of spherical porous β-tricalcium phosphate (SPTCP). Case presentation: We present our first four clinical cases of opening-wedge high tibial osteotomy (OWHTO) using UDPTCP and SPTCP together. The patients' mean age was 54.5 ± 5.9 years, and the mean observation period was 20.8 ± 2.8 months. In OWHTO, two wedge shaped pieces of UDPTCP and SPTCP were cut to fit the gap and implanted parallel to each other in the anterior and posterior parts, respectively. We evaluated the correction loss and bone remodeling for UDPTCP and SPTCP over time using radiography and computed tomography, and evaluated the clinical outcomes. Conclusion: There was no correction loss reported in any case, and early bone remodeling was observed with UDPTCP. All patients achieved satisfactory clinical results with no adverse events.